Because of a combination of not having money and being scared of car wrecks and scared of being judged by people because of my age. I live somewhere that has a pretty big car/truck culture and those in their 20s and 30s who don't drive or don't like vehicles are judged pretty harshly.

Not to mention, drivers schools here want things like parent's signatures and what not and I can't provide that beings I don't have parents.

I'm eventually planning on moving to a major city with good public transportation so I won't need to drive to have reliable transportation. Plus I might eventually learn when I'm living somewhere where it's more socially acceptable for young people to not drive because of good public transportation or high cost of living or something else.